A prior art multi-element capacitor (see: Application PCT WO 2009103661, cl. H01G 9/155, published on Aug. 27, 2009, 34 pages) comprises at least two adjacent composite electrodes separated by a spacing d and at least one composite electrode common for the aforesaid electrodes and held apart therefrom by a separator, the composite electrodes being coiled together into a roll.
This design gives rise to unavoidable problems in providing reliable low-resistance contact between the electrode and the commutator. Furthermore, discontinuity of the electrode material may cause undesirable reaction between the electrolyte and the commutator material that may, in turn, reduce the operating voltage of the capacitor by the electrochemical decomposition potential of the commutator. Absence of insulation between the adjacent capacitor electrodes is another major deficiency of the design reducing voltage and, therefore, specific energy of the capacitor. As a result, when capacitor sections are connected in series the potential differentials of the electrodes may be double the operating voltage of the capacitor elements. This is likely to initiate electrochemical electrode reactions limiting the lifetime of the capacitor.
A prior art method for manufacturing a multi-element capacitor is described in Application PCT WO 2009103661, cl. H01G 9/155, published on Aug. 27, 2009, 34 pages. According to the prior art method, an electrode is placed between two separators that are actually separating bands, with two composite electrodes placed at a distance d between them on the top band. The bands and the electrodes are then coiled into rolls.
The prior art invention is disadvantageous because the multi-element capacitor comprises individual components in the form of spaced electrodes that are difficult to be combined into a multi-element assembly, particularly in a continuous roll-making process. The use of a multilayered composite structure comprising an electrode applied to the metal commutator surface is another disadvantage of the prior art invention.